There are generally two schools of thought when it comes to knuckle-cracking, the first being that cracking happens when two bones are stretched to the point of cracking, creating a bubble in the joint; and the other that it is a result of bubbles collapsing in the joint.

Two studies have taken place, one by Dr Mahsa Tehrani who said: “Right after cracking, the joint space is not altered in any way, whereas previously it was thought that by cracking your joints, you increased the joint space. Occasional knuckle-cracking shouldn’t have any major ramifications. The finding that the joint rebounds back to its normal position after knuckle-cracking supports this.”

"There is no evidence that knuckle-cracking will lead to arthritis. However, you should be aware that part of getting knuckles to crack entails the gliding of tendons past one another. Whenever there is excessive repetitive activity in the tendons, the risk of inflammation also increases. Therefore, if you are looking to pick up a new hobby, knuckle-cracking should not be at the top of your list.”

The other by Robert Boutin, Professor of radiology at the University of California analysed 40 volunteers cracking the bottom joint on their fingers, some who were habitual knuckle-crackers, and some had never intentionally done it before.

“We were interested in pursuing this study because there’s a raging debate about whether the knuckle-cracking sound results from a bubble popping in the joint or from a bubble being created in the joint.”

“We found that there was no immediate disability in the knuckle crackers in our study, although further research will need to be done to assess any long-term hazard – or benefit – of knuckle-cracking.”

While studies have taken place to test both theories, they essentially came to the same conclusion.